Lo Rabindranath, Ganguly Bishwajit
Computation and Simulation Unit (Analytical Discipline and Centralized Instrument Facility), CSIR-Central Salt & Marine Chemicals Research Institute, Bhavnagar, Gujarat 364 002, India.
Computation and Simulation Unit (Analytical Discipline and Centralized Instrument Facility), CSIR-Central Salt & Marine Chemicals Research Institute, Bhavnagar, Gujarat 364 002, India.
J Mol Graph Model. 2015 Feb;55:123-33. doi: 10.1016/j.jmgm.2014.11.008. Epub 2014 Nov 28.
A computational study has been performed using MP2 and CCSD(T) methods on a series of O⋯X (X=Br, Cl and I) halogen bonds to evaluate the strength and characteristic of such highly directional noncovalent interactions. The study has been carried out on a series of dimeric complexes formed between interhalogen compounds (such as BrF, BrCl and BrI) and oxygen containing electron donor molecule. The existence and consequences of the anomeric effect of the electron donor molecule has also been investigated through an exploration of halogen bonding interactions in this halogen bonded complexes. The ab initio quantum chemical calculations have been employed to study both the nature and directionality of the halogen molecules toward the sp(3) oxygen atom in anomeric systems. The presence of anomeric nO→σ*CN interaction involves a dominant role for the availability of the axial and equatorial lone pairs of donor O atom to participate with interhalogen compounds in the halogen-bonded complexes. The energy difference between the axial and equatorial conformers with interhalogen compounds reaches up to 4.60 kJ/mol, which however depends upon the interacting halogen atoms and its attaching atoms. The energy decomposition analysis further suggests that the total halogen bond interaction energies are mainly contributed by the attractive electrostatic and dispersion components. The role of substituents attached with the halogen atoms has also been evaluated in this study. With the increase of halogen atom size and the positive nature of σ-hole, the halogen atom interacted more with the electron donor atom and the electrostatic contribution to the total interaction energy enhances appreciably. Further, noncovalent interaction (NCI) studies have been carried out to locate the noncovalent halogen bonding interactions in real space.
利用MP2和CCSD(T)方法对一系列O⋯X（X = Br、Cl和I）卤键进行了计算研究，以评估此类高度定向非共价相互作用的强度和特性。该研究针对卤间化合物（如BrF、BrCl和BrI）与含氧化合物电子供体分子之间形成的一系列二聚体配合物展开。通过探究该卤键配合物中的卤键相互作用，还研究了电子供体分子端基异构效应的存在及其影响。采用从头算量子化学计算方法研究了卤键体系中卤分子与sp(3)氧原子之间的作用本质和方向性。端基异构nO→σ*CN相互作用的存在，表明供体O原子的轴向和赤道孤对电子在卤键配合物中与卤间化合物参与作用时起主导作用。卤间化合物轴向和赤道构象体之间的能量差高达4.60 kJ/mol，但这取决于相互作用的卤原子及其连接原子。能量分解分析进一步表明，总的卤键相互作用能主要由吸引性静电和色散成分贡献。本研究还评估了与卤原子相连取代基的作用。随着卤原子尺寸的增大以及σ-空穴正性的增强，卤原子与电子供体原子的相互作用增强，静电作用对总相互作用能的贡献显著提高。此外，还进行了非共价相互作用（NCI）研究，以在实空间中定位非共价卤键相互作用。
